Loose lock current: Before giving the loose lock command, the inverter should first establish the loose lock current. The current is generally set at 70% ~ 120% of the rated motor current. In general, the current dynamic response fast frequency converter, this current can be set lower; Current dynamic response slow frequency converter, this current must be set higher. Lifting mechanism and outdoor crane translation mechanism, rotary mechanism this current needs to be set higher; Indoor crane translation mechanism and rotary mechanism this current can be set lower. The current value is set low, the motor torque is not enough when the lock is loose, the lifting mechanism will slip the hook phenomenon (full load), the translation mechanism will move in different directions (due to wind or slope); This current value is set high, the brake is not opened when the blocking current is large, unfavorable to the motor. It should be noted in particular that this current is also directional: for the lifting mechanism, the direction of this current is always positive (lifting direction), for the translation mechanism and the rotation mechanism, the direction of this current should be the same as the direction of motion.
